An increasing number of applications require illumination systems that are small in size but high in intensity. Light sources such as LEDs typically have been used as indicator lights, but have not been used for projection or illumination systems because LEDs typically lack the required intensity. LEDs are desirable sources for many applications, however, due to their small size, low cost, and ease of use. Another problem with LEDs is that they typically are not able to produce a high quality color spectrum. Some existing systems utilize a single blue LED with a phosphorus conversion layer to produce white light. However, the output spectrum of this device is fixed and cannot be varied during use.